JP2007304228A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus capable of performing control suitable for additional printing by automatically detecting paper as an additionally printed paper even without input of information showing that it is the paper to be additionally printed. <P>SOLUTION: The image forming apparatus has: a paper supply device 100 for storing image forming paper P; a feeding roller 113 taking out the paper P in the paper supply device 100 and separating and feeding it; a paper loosening roller 114 press-contacting with the feeding roller; a roller cleaning means 116 cleaning the feeding roller 113 and/or the paper loosening roller 114; and a paper color detection means 120 detecting the image forming surface of the paper P fed by the feeding roller 113 and detecting whether or not a plurality of colors exist on the image forming surface. When the paper color detection means 120 detects two or more colors from the paper P, the paper P is judged as already printed paper, and additional printing control is performed. Whether to perform the additional printing is automatically judged without inputting information showing that it is the printed paper. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic image forming apparatus such as an electronic copying machine, a printer, and the like, particularly in a case where additional printing (reprinting) is performed on a sheet on which a pattern or a character has already been printed. , Concerning reprint control.

  In the image forming apparatus, it is necessary to feed the sheets stored in a stacked state in the sheet feeding apparatus one by one to the image forming unit, and the sheet is not properly fed or a plurality of sheets are overlapped to feed. Therefore, it is required to effectively prevent the double feed.

  As a conventional paper feeding method, a friction separating roller type is well known. In this paper feeding device, the uppermost sheet of paper placed in the paper feeding device is taken out by a pickup roller and separated one by one by a paper feeding means comprising a feeding roller and a separating roller with a torque limiter. It is configured to feed paper to the conveyance path.

  By the way, in the case of printed matter such as direct mail where the text part is common and only the address part is different, the text part is printed on another printing machine, and only the address part is printed on the image forming apparatus. Use it like printing.

  In this case, as the paper, a paper on which a pattern, characters, etc. are already printed is used. By the way, if the printed sheets are stacked as they are, the ink on which the pattern and the characters are drawn adheres to the back of the sheet placed on the sheet and stains the sheet. In order to prevent this, a large amount of anti-back-through agent called dust is applied to the printing surface.

  When feeding paper that has been sprinkled with a large amount of dust in this way, this dust will gradually adhere to the feed roller and the scooping roller, and eventually these rollers will become dirty and cause poor feeding. It becomes.

With respect to this problem, in Patent Document 1, information such as the size, type, and amount of paper stored in a plurality of paper feeders is stored in a paper information input unit in association with the paper feeder, and a sheet with a lot of dust. When a specific sheet is selected, the transport time in a predetermined section of a specific type of paper fed from the selected paper feeding device is detected, and when the transport time becomes longer than a predetermined value, A system has been proposed in which one or both of a feeding roller and a separating roller of a sheet feeding device are cleaned by a roller cleaning unit for a predetermined time.
JP 2004-359449 A

  However, in Patent Document 1, it is necessary to input and memorize in which paper feeding device a specific type of paper is stored in the paper information means. If this input is forgotten, control of reprinting such as cleaning is performed. There was a problem that it would be impossible.

  The present invention is intended to solve such a problem. Even if it is not input that the paper is for reprint, it is automatically detected as reprint paper, and control suitable for reprint is performed. An image forming apparatus capable of performing the above is provided.

  In order to achieve the above object, an image forming apparatus of the present invention includes a sheet feeding device that can store sheets for image formation in a stacked state, and a feeding roller that takes out the sheets in the sheet feeding apparatus and separates and feeds them. A paper roller that is in pressure contact with the feed roller, a roller cleaning unit that cleans the feed roller and / or the paper roller, and an image forming surface of the paper that is fed by the feed roller is detected on the image forming surface. And paper color detection means for detecting whether or not there are a plurality of colors.

  The sheet color detection unit includes a sheet counter that counts the number of sheets having a plurality of colors, or includes a dust removal unit that removes deposits on the image forming surface. The paper device has a structure that has an air exhaust port for sending air from the side of the paper feeding direction to the top of the stacked paper, or the image forming device has a display device, and the display device has the number counter. Depending on the number of sheets, it is possible to display a part replacement time and a part cleaning time.

  According to the present invention, it is possible to automatically identify whether or not the paper supplied by the paper feeder is already printed, and to identify only the paper to be overprinted, so that the operator forgets to input the type of paper. This has the special effect of preventing this.

  By providing a sheet counter that counts the number of sheets to be reprinted, it is possible to automatically perform reprint control such as cleaning for each predetermined number of sheets.

  By providing the dust removing means for removing the deposits on the image forming surface, it is possible to reduce the contamination of the feeding roller and the scooping roller and to extend the cleaning cycle and the component replacement cycle.

  By blowing air from the air exhaust port to the upper part of the stacked sheets, the sheets can be separated one by one and double feeding can be prevented.

  By making the display device indicate the parts replacement time and the parts cleaning time, it is possible to replace the consumable parts at an appropriate period and to clean the parts at an appropriate period.

  FIG. 1 is an example of an image forming apparatus according to the present invention, and is a diagram showing a configuration of an image forming apparatus 1 that is a digital copying machine.

  A document placement plate 10 on which the document G is placed is provided on the upper portion of the image forming apparatus 1. The original G is read by a mirror 12 that moves integrally with the exposure lamp 11, V-shaped mirrors 13 and 14 that move half the moving distance of the mirror 12, an imaging lens 15, and a CCD 16. .

  On the outer periphery of the drum-shaped photosensitive member 21, a charger 22, a developing unit 23, a transfer unit 24, a separator 25, and a cleaning device 26 are arranged in the order of operation.

  Digital image data read by the CCD 16 is superimposed on laser light emitted from a laser (not shown) and scanned by a polygon mirror 31. The scanned laser light is reflected by the mirrors 32 and 33 and forms an original image on the photosensitive member 21 through the fθ lens 34, the cylindrical lens 35, and the mirror 36. The photosensitive member 21 is charged on the surface of the photosensitive layer by the charger 22 and forms an electrostatic latent image corresponding to the original image on the photosensitive layer surface by forming an original image.

  When the electrostatic latent image reaches the developing device 23, toner adheres to the electrostatic latent image to become a toner image, and a visible image is formed.

  Further, a double-sided copying paper feeding device 40 and paper feeding devices 50a, 50b, and 50c are arranged in a vertical position below the image forming apparatus 1, and the paper feeding devices 50a, 50b, and 50c have different sizes. A sheet P as a recording medium is stored.

  When the paper P stored in any of the paper feeding devices 50a, 50b and 50c is selected, only one paper P is fed by the pickup roller 51 provided in the paper feeding device, and this paper P is fed. It is conveyed by the delivery roller 52.

  Then, the paper P is transported along the transport path 60 toward the photoconductor 21 on which the toner image is formed. Then, the paper P is temporarily stopped by the registration roller 62, and paper is fed so that the toner image formed on the photosensitive member 21 and the paper P coincide with each other.

  Next, the toner image on the photoconductor 21 is transferred to the paper P by the transfer device 24, and the paper P is separated from the surface of the photoconductor 21 by the separator 25. Then, the paper P is transported to the fixing device 70 by the transport device 63.

  The fixing device 70 includes a heating roller 71 and a pressure roller 72, and the toner image on the paper P is stably fixed on the paper P by the heating roller 71 and the pressure roller 72.

  The sheet P that has been fixed is discharged by a discharge guide roller 74. In the case of single-sided copying, the paper discharge switching member 75 is lowered and the paper P is discharged to the paper discharge tray 76 as it is.

  In the case of duplex copying, the paper discharge switching member 75 is raised, the paper guide unit 77 is opened, and the paper P is conveyed downward.

  Then, the paper P is transported downward by the transport mechanism 78 and is switched back by the paper reversing unit 79, and the rear end of the paper P becomes the leading end and is transported into the duplex copying paper feeder 40.

  The paper P is moved in the paper feeding direction by a conveyance belt 41 provided in the double-sided copying paper feeding device 40, the paper P is re-fed by a paper feeding roller 42, and the paper P is guided to the conveyance path 60.

  Again, as described above, the paper P is conveyed in the direction of the photosensitive member 21, the toner image is transferred to the back surface of the paper P, fixed by the fixing device 70, and then discharged onto the paper discharge tray 76.

  FIG. 2 is a diagram schematically illustrating a configuration of the paper feeding device 100 of the image forming apparatus 1 of the present invention, and FIG. 3 is a perspective view of a main part of the paper feeding device 100.

  The paper feeding device 100 is a paper feeding device that is capable of feeding a large-capacity paper of a normal size and switching the size, unlike the paper feeding devices 50a, 50b, and 50c of various sizes described above. In other words, a large amount of frequently used paper P (recording medium) is loaded to reduce the replenishment frequency and efficiently feed paper. Incidentally, the most frequently used paper size is the A4 size, and the postcard size is frequently used in some industries. Therefore, it is desired to provide a large capacity sheet feeding device that can use both sizes.

  As shown in FIG. 3, box-shaped positioning members 102 and 102 that determine the left and right positions of the paper P are provided on the left and right sides of the paper P. These positioning members 102 and 102 are configured to be able to advance and retreat in a direction orthogonal to the advancing direction of the paper P indicated by the arrow b, and position the paper P in the left-right direction in the advancing direction. Although not shown, a positioning member for positioning the rear end of the paper P is also provided.

  A wind fan 104 is fitted in the positioning member 102, and an air exhaust port 106 of the wind fan 104 is opened above the stacked sheets P. The uppermost surface of the paper P is located approximately in the middle of the air exhaust port 106. Then, when the blower fan 104 rotates, the wind from the air exhaust port 106 blows into the upper part of the paper P, and the air is sent between the paper P to separate the paper P one by one.

  The paper P placed on the tray 111 of the paper feeding device 100 is arranged so that the uppermost surface of the paper P becomes a certain height by raising and lowering the tray 111 and the sensor 117 that detects the position of the uppermost surface of the paper P. The uppermost paper P that has been adjusted is pressed against the pickup roller 112. Then, the pickup roller 112 is rotated in the paper feeding direction (the direction of the arrow a in the drawing) to distribute the paper P from the paper feeding device 100.

  The paper P sent out by the pickup roller 112 is fed to the transport roller 115 by the feed roller 113 and enters the transport path 60. Usually, the shaft of the delivery roller 113 is connected to the driving means, and the rotation of the delivery roller 113 is transmitted to the pickup roller 112 by a belt or the like.

  The separating roller 114 that is in pressure contact with the lower portion of the feed roller 113 is connected to a drive shaft via a torque limiter (not shown), and the drive shaft normally rotates in a direction opposite to the paper feeding direction. When the paper P in the paper feeder 100 is double-fed, the second and subsequent sheets P can be peeled off from the first sheet with a small force, and the separating roller 114 is used for the second and subsequent sheets. P is sent back and sent back to the paper feeder 100.

  On the other hand, when the paper is properly fed, there is only one paper P. Therefore, the paper P cannot be reversely fed with a small torque applied to the rolling roller 114, the torque limiter idles and rotates following the feed roller 113, and the paper P is fed in the paper feeding direction.

  As described above, a large amount of dust is applied to the printed paper in order to prevent the ink from getting dirty on the back of the adjacent paper. This surplus of dusting powder adheres to the surface of the paper P, or paper dust is generated from the surface of the paper P. Since these adhere to the feeding roller 113 and the whirling roller 114 and cause dirt on the rollers, the sending roller 113 is provided with roller cleaning means 116 that presses against the feeding roller 113 on the outer peripheral surface. The roller cleaning means 116 is composed of a sponge-like roller made of foamed urethane, and is rotated in the same direction as the rotation direction of the delivery roller 113, thereby moving in the opposite directions on the contact surface and paper adhering to the delivery roller 113. Powder etc. are removed by rotational friction. In this embodiment, an example in which the roller cleaning means 116 is disposed only on the feeding roller 113 is shown as an example. However, the roller cleaning unit 116 is disposed only on the separating roller 114 or disposed on both the conveying roller 113 and the separating roller 114. Also good.

  Further, on the paper P between the positioning member 102 and the pickup roller 112, a dust removing unit 119 for removing the deposits such as the dust and paper dust is provided. In the embodiment, a vacuum suction nozzle is used as the dust removing means 119.

  A paper color detection unit 120 is provided in the conveyance path from the delivery roller 113 to the conveyance roller 115. The paper color detection unit 120 scans the image forming surface of the paper to determine whether or not the paper P is already printed.

  FIG. 4 is a diagram illustrating a state in which the paper color detection unit 120 determines whether the paper P is a printed paper. The paper color detection unit 120 is composed of a line sensor having the same length as the width of the paper P, and feeds the paper P in the direction of the arrow to scan the entire image forming surface of the paper P. If the paper P is one color, it is determined that the paper is not printed, and if two colors are detected from the paper P, it is determined that the paper has already been printed. In the example of FIG. 4, since there is a gray portion in part of the white paper P, it is determined that the paper is a printed paper.

  As the paper color detecting means 120, various devices such as a scanning optical system line sensor and a device using a CCD array can be used.

  FIG. 5 is a block diagram of a control system of the image forming apparatus of the present invention. The overall control unit 200 is for cooperating each device attached to the image forming apparatus, is configured mainly by a computer, has a CPU and a storage device (not shown), and installs a control program such as image processing. Has been. Further, it includes a follow-up printing control unit 210, an operation panel control unit 220, a dust removing means driving circuit 230, a cleaning roller driving circuit 240, and a fan driving circuit 250. The dust removing means driving circuit 230 controls the dust removing means 119, the cleaning roller driving circuit 240 controls the roller cleaning means 116, and the burning fan driving circuit 250 controls the burning fan 104.

  The reprint control unit 210 is a part that performs control when performing reprinting on printed paper. Here, a sheet counter 211 that counts the number of reprints, a cleaning instruction unit 212 that notifies the cleaning roller drive circuit 240 when the count number of the sheet counter 211 reaches a predetermined value, and displays on the display device 221. A replacement part instruction unit 213 for displaying part replacement on the display device 221 is provided.

  The display device 221 includes a liquid crystal touch panel in addition to a numeric keypad and various push button switches. When an operator inputs a numerical value or various settings such as the paper size or the number of copies from here, the operation panel control unit 220 displays the touch panel. The contents are transmitted to the overall control unit 200.

  The sheet number counter 211 counts the number of sheets P on which the sheet color detecting unit 120 detects two or more colors.

  FIG. 6 is a flowchart illustrating a method for performing reprint control in the image forming apparatus of the present invention. This will be described below.

  When the image forming apparatus 1 is instructed to start printing (image formation) (# 101), the paper P is supplied from the paper feeding apparatus 100. The paper color detection means 120 detects whether or not the supplied paper P is already printed (# 102). If the paper P is one color, it is determined that the paper is not printed, printing is performed as instructed, and the process ends (# 103).

  If the paper P is two or more colors, it is determined that the paper P has already been printed and is to be overprinted, and it is confirmed whether the fan 104 and the dust removing means 119 are operating (# 104). . If these are stopped, the dust removing means driving circuit 230 and the fan driving circuit 250 are operated (# 105), and at the same time, the sheet counter 211 counts the number of reprinted sheets of paper P.

  The wind fan 104 rotates and winds so as to separate the sheets P one by one with the wind blown from the air exhaust port 106. Further, the dust removing means 119 sucks the upper surface of the fed paper P and sucks and collects the adhering dust.

  When the number of sheets in the sheet counter 211 reaches a preset number (# 106), the cleaning instructing unit 212 drives the cleaning roller driving circuit 240 to rotate the roller cleaning means 116 and press against the feeding roller 113 for sending. Cleaning of the roller 113 is started (# 107). The dust or the like adhering to the rolling roller 114 is transferred to the delivery roller 113 and indirectly cleaned.

  If it is determined that the time during which the roller cleaning means 116 is rotating in pressure contact with the delivery roller 113 has reached a preset time (# 108), the cleaning roller drive circuit 240 sends the roller cleaning means 116 to the delivery roller. Separate from 113 and complete cleaning (# 109). The above is continued until printing is completed, and the process ends (# 110). During this time, the image forming operation can be continued.

  When the paper P with a lot of dust is used, the dust contains oil, so that the oil evaporates in the fixing device 70 and floats in the image forming apparatus 1 to be separated from the charger 22 and the transfer device 24. It adheres to electrodes such as the vessel 25. Therefore, when the number of reprints reaches a certain number, the replacement part instruction unit 213 displays “It is time to replace the electrode unit” on the screen 221a of the display device 221 as shown in FIG. .

  In the above embodiment, the paper feeder 100 has been described. However, the roller cleaning unit 116 and the paper color detection unit 120 are also provided in the other paper feeders 50a, 50b, and 50c, respectively, so that the overprinting control is similarly performed. Can do.

1 is a diagram illustrating a configuration of an image forming apparatus that is a digital copying machine as an example of an image forming apparatus according to the present invention. 1 is a diagram schematically illustrating a configuration of a sheet feeding device of an image forming apparatus of the present invention. It is a principal part perspective view of a paper feeder. It is a figure which shows the state which judges whether a paper color is printed by the paper color detection means. 2 is a block diagram of a control system of the image forming apparatus of the present invention. FIG. 6 is a flowchart illustrating a method for performing follow-up printing control in the image forming apparatus of the present invention. It is a figure which shows the example of a display of components replacement | exchange.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Image forming apparatus 100 Paper feed apparatus 104 Separation fan 106 Exhaust port 112 Pickup roller 113 Sending roller 114 Separation roller 115 Conveyance roller 116 Roller cleaning means 119 Dust removal means 120 Paper color detection means 210 Reprint control section 211 Number counter 212 Cleaning instruction Part 213 Replacement part instruction part 220 Operation panel control part 221 Display device 230 Dust removal means drive circuit 240 Cleaning roller drive circuit 250 Whisper fan drive circuit

Claims (5)

  A sheet feeding device that can store sheets for image formation in a stacked state, a feeding roller that takes out the sheets in the sheet feeding device and separates and feeds them, a separating roller that is in pressure contact with the feeding roller, the feeding roller and / or Or roller cleaning means for cleaning the roller, and paper color detection means for detecting the image forming surface of the paper fed by the delivery roller and detecting whether or not there are a plurality of colors on the image forming surface. And an image forming apparatus.   2. The image forming apparatus according to claim 1, further comprising a number counter that counts the number of sheets having a plurality of colors detected by the sheet color detecting unit.   The image forming apparatus according to claim 1, further comprising a dust removing unit that removes deposits on the image forming surface.   4. The image forming apparatus according to claim 1, wherein the paper feeding device has an air exhaust port that feeds air from above a side of the paper feeding direction to the top of the stacked paper.   5. The image according to claim 1, wherein the image forming apparatus includes a display device, and the display device displays a part replacement time and a part cleaning time according to the number of the number counters. Forming equipment.

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